Rosalina is a tall character in Super Smash Bros. Wii U, but very light, according to Masahiro Sakurai. You can tell from the shot below that she's considerably taller than Mario, but since she sports an anti-gravity effect, she doesn't weigh a lot.

The other shots show Toad being held hostage, a roundup of yellow characters and a few more things. Check them all out below.

I liked that trailer with them riding the karts. HOPEFULLY, we'll see cross over in mario kart, here's hoping that they add in Link, Kirby, Diddy Kong and Captain Falcon to Mario Kart 8!!

The trailer might actually be a hint towards Kirby being in mario kart 8.

2 birds 1 stone kinda deal... I mean it IS possible, Kirby air ride is bad but it still exists and shows Kirby is capable of racing. And he was seen alongside other typical mario kart racers in the smash trailer

And think about it, technically diddy and funky have nothing to do with mario (though more to o with maio than kirby has anyway) but they were in the previous game, same with rob in mkds.